High-strength, lightweight blow-molded plastic structures

ABSTRACT

Blow-molded plastic structures may include a plurality of depressions and the depressions may have different characteristics depending, for example, upon the particular configuration of the depression. For example, a depression may have an elongated length and it may have increased strength along its length. The depressions may be arranged into a pattern in order to take advantage of particular characteristics of the depressions. For example, the depressions may be arranged to maximize the strength and/or minimize the weight of the structure. The depressions may also be arranged to create a structure with generally uniform characteristics. Significantly, the depressions may be arranged into a number of different patterns depending, for example, upon the intended use of the structure. For instance, the depressions may be arranged into a pattern with one or more rows and columns, and the depressions may be disposed in particular positions or orientations within the rows or columns.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and the benefit of, U.S. provisional patent application Ser. No. 60/659,982, filed Mar. 9, 2005, which is incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to structures constructed from blow-molded plastic and, in particular, to high-strength, lightweight blow-molded plastic structures.

2. Description of Related Art

It is known to construct various objects and items, such as tables, chairs, partitions, walls, and sports equipment, from plastic. It is also known to construct some of these and other objects from blow-molded plastic. As known to those skilled in the art, blow-molded structures often include an outer wall that encloses a hollow interior space. Because blow-molded structures include a hollow interior space, many blow-molded structures are not high-strength. In fact, many known blow-molded structures are relatively low-strength and are unable to support a relatively large amount of weight or force.

In order to increase the strength of conventional blow-molded structures, it is known to add strengthening ribs. For example, known tables with table tops constructed from blow-molded plastic may include strengthening ribs attached to the underside of the table top in an attempt to increase the strength of the table top. The strengthening ribs are often constructed from metal because metal ribs are high strength. Disadvantageously, the metal ribs must be attached to the table top by mechanical fasteners such as bolts or screws. The bolts or screws require holes in the table top, which may create stress concentrations and/or potential failure points in the table top. Alternatively, the metal ribs may be attached to the table top by adhesives, but the adhesives may also decrease the structural integrity of the table top and make the table top very difficult to repair or replace. In addition, the metal ribs may increase the number of components required to construct the table and the time required to manufacture the table. Thus, while it is known to use metal ribs to increase the strength of a blow-molded table top, the metal ribs may undesirably increase the time and costs to manufacture the table. Further, the attachment of the metal ribs to the table top may decrease the strength and/or structural integrity of the table top, and increase the potential causes of failure of the table.

Conventional table tops constructed from blow-molded plastic may also include strengthening ribs or beams that are integrally formed in the table top. For example, strengthening ribs may be formed in the underside of the center portion of the table top in an effort to prevent sagging of that portion of the table top. These strengthening ribs are generally large, elongated portions that extend along the length or width of the table top. While the strengthening ribs may increase the strength or structural integrity of the table top, the ribs often require thicker outer walls so that the large, elongated ribs are correctly formed in the table top. The large, elongated strengthening ribs may also require thicker outer walls so that the ribs do not undesirably sag or deform during the manufacturing process. Disadvantageously, the thicker outer walls of the ribs may require additional plastic materials be used to create the table top, which may undesirably increase the costs and weight of the table tops. In addition, the thicker outer walls may retain more heat during the manufacturing process. Thus, a longer cooling time may be required during the manufacturing process in order to allow the thicker outer walls to cool. This may undesirably increase the time of the manufacturing process because the blow-molded table tops cannot be removed from the mold until the tops are sufficiently cooled.

Known table tops constructed from blow-molded plastic may also include strengthening ribs disposed in other portions of the table top. For example, strengthening ribs may be placed near opposing ends of the table top in an effort to increase the strength of the ends of the table top. Additionally, these strengthening ribs may be configured to help prevent the table top from undesirably bending and to allow the table top to support additional weight. The strengthening ribs, however, often protrude outwardly from the underside of the table top and the ribs frequently have relatively large profiles to help create relatively strong supporting structures. Disadvantageously, the large, protruding ribs may undesirably decrease the amount of room underneath the table top, decrease the usefulness of the table and limit potential design considerations and/or arrangements of the table top.

Conventional table tops that are constructed from blow-molded plastic and include strengthening ribs, however, may still not have sufficient strength and may allow a portion of the table top to sag. In order to increase the strength of these conventional table tops, it is known to increase the number of ribs. These additional ribs undesirably require a larger area on the underside of the table top, which may limit the area that other features may be formed in the table top. The numerous strengthening ribs may also interfere with other features or components of the table, such as interfering with the folding of the table legs into a collapsed position. The ribs may also increase the cooling and manufacturing time of the table top.

Additionally, while the large strengthening ribs may prevent large portions of the table top from sagging, the ribs may allow smaller, localized portions of the table top to sag. In particular, because the distance between the table top and the bottom portion of the rib is greater than the distance between the upper and lower surfaces of the table top, this may allow localized portions of the table top to sag. Additionally, because the strengthening ribs are large and have an elongated length, they may support localized portions of the table top differently than the other portions of the table top. Thus, the upper surface of the table top may be uneven because different portions of the table top are supported differently.

BRIEF SUMMARY OF EMBODIMENTS OF THE INVENTION

A need therefore exists for structures constructed from blow-molded plastic that eliminates or reduces some or all of the above-described disadvantages and problems.

One aspect is a structure that can be constructed from blow-molded plastic and have increased strength. Preferably the blow-molded plastic structure has both increased strength and it is lightweight, but the structure does not have to be lightweight and high-strength.

Another aspect is a structure that can be constructed from blow-molded plastic and include opposing surfaces. The opposing surfaces may be separated by a generally constant or other predetermined distances. For example, the opposing surfaces may include one surface that is generally planar and the other surface may include a plurality of depressions that are sized and configured to increase the strength of the blow-molded structure. The depressions may cover only a portion of the surface, substantially all of the surface, or the entire surface.

Yet another aspect is a structure that can be constructed from blow-molded plastic and the structure could have a variety of suitable shapes and configurations, and the structures could be an assortment of items and objects such tables, chairs, walls, shelves, storage bins, boxes, containers, sheds, panels, fences, playground equipment, sports equipment and the like. In particular, the structures could be used to form all or a portion of a table and basketball backboard. Desirably, the upper surface of the tables and the front surface of the backboards are generally planar, while the bottom or rear surfaces include a plurality of depressions. It will be appreciated, however, that the structures could have any desired arrangement or design.

Still another aspect is a structure that can be constructed from blow-molded plastic and the structure can include a plurality of depressions. Desirably the distance between the depressions may be substantially decreased, which may substantially increase the number of depressions formed in the blow-molded structure. This increase in the number of depressions formed in the blow-molded structure at first appears to increase the amount of plastic material required to construct the structure because of the increased surface area and number of depressions. The increased number of depressions with the increased amount of plastic also appears to increase the time the structure must be cooled during the manufacturing process. In particular, the increased amount of plastic may retain more heat and that would require a longer cooling time before the structure could be removed from the mold. Disadvantageously, if the structures cannot be removed as quickly from the mold, then this would increase the cycle time required to construct the blow-molded structures, which may increase costs and time required to manufacture the structures. The increased number of depressions and closer spacing of the depressions, however, allows the outer wall of the blow-molded structure to be constructed from thinner plastic. Thus, contrary to conventional blow-molded structures, increasing the number of depressions allows blow-molded structures with thinner walls to be constructed. Significantly, the thinner walls allow less plastic to be used to construct the blow-molded structure. The reduced amount of plastic advantageously saves materials and resources. In addition, the costs of the blow-molded structure may be decreased because less plastic is required. Further, lightweight structures may be constructed if less plastic is required to make the structure.

A further aspect is a structure that can be constructed from blow-molded plastic with thinner outer walls and that may allow heat to be dissipated more quickly during the manufacturing process. Because the thinner outer walls allow heat to be dissipated more quickly, the blow-molded structures may cool more quickly and this may allow structures to be removed sooner from the mold. Additionally, because the increased number of depressions may provide more support for the opposing surfaces, the structures may be removed from the mold at a higher temperature. Accordingly, the manufacturing time and/or cycle time required to construct the blow-molded structures may be reduced, which may increase the output and/or efficiency of making the structures.

Yet another aspect is a structure that can be constructed from blow-molded plastic and conventional reinforcing ribs and beams are not required. In fact, reinforcing ribs or beams are desirably not formed in the blow-molded structures because the ribs may require thicker outer walls and increase the time of the manufacturing process. The reinforcing ribs may also undesirably interfere with other structures or features formed in the table top. In addition, the structure may have a lower profile because reinforcing ribs are not required. Advantageously, this may allow the height or thickness of the blow-molded structures to be decreased.

A further aspect is a structure that can be constructed from blow-molded plastic and the depressions may be uniformly spaced to create generally consistent and/or standardized arrangements. A consistent arrangement of the depressions may help create a structure with uniform characteristics. For example, a generally constant pattern of depressions may create a structure with generally uniform strength and structural integrity.

A still further aspect is a structure that can be constructed from blow-molded plastic and the structure may include one or more generally planar surfaces. Desirably the structure includes a plurality of closely spaced depressions on one side and a generally planar surface on the other side. This may allow blow-molded structures with large generally planar surfaces, such as tables and basketball backboards, to be quickly and efficiently manufactured and constructed. In addition, the closely spaced depressions may allow large planar surfaces to be created that do not include significant sags, ripples or uneven surfaces.

Another aspect is a structure that may be constructed from blow-molded plastic and include a plurality of depressions that are formed in one surface and extended towards another surface. The depressions may have different characteristics depending upon the configuration of the depression. For example, the depressions may have a length and a width and the characteristics of the depressions may be different for the length and the width. In particular, the depression may have increased strength along its length in comparison to its width.

Still another aspect is a structure that may include a plurality of depressions and the depressions may have a non-circular configuration, such as rectangular, oblong, oval and the like, and different characteristics. The depressions may also have different characteristics depending upon the configuration of the depression. For example, the depressions may have a non-circular configuration with increased strength in one direction in comparison to another direction. Advantageously, if the depressions have different characteristics, then the depressions can be arranged or configured so that the structure has certain characteristics. In particular, the depressions may be arranged into a pattern so that characteristics are maximized and/or the structure has generally uniform characteristics. Thus, the depressions may be aligned or otherwise formed into a pattern to maximize or minimize one or more of these characteristics.

Yet another aspect is a structure that is constructed from blow-molded plastic and includes depressions having the same generally shape. Advantageously, the depressions may be arranged into a pattern, such as a parallelogram. In particular, a first depression may be disposed proximate second and fourth depressions. The second depression may be disposed proximate the first and third depressions. The third depression may be disposed proximate the second and fourth depressions. The fourth depression may be disposed proximate the first and third depressions. The first and third depressions may be positioned at opposing corners of the generally parallelogram shaped configuration, and the second and fourth depressions may be positioned at the other opposing corners. A fifth depression may be positioned proximate a central portion of the generally parallelogram shaped configuration. The fifth depression may be orientated at first angle. The first depression may be disposed at an angle that is oblique to the first angle. The second depression may be disposed at an angle that is oblique to the first angle. The third depression may be disposed at an angle that is oblique to the first angle. The fourth depression may be disposed at an angle that is oblique to the first angle.

Still yet another aspect is a structure constructed from blow-molded plastic with a plurality of depressions in a generally parallelogram shaped configuration. The first depression may be disposed proximate the second and fourth depressions. The second depression may be disposed proximate the first and third depressions. The third depression may be disposed proximate the second and fourth depressions. The fourth depression may be disposed proximate the first and third depressions. The first and third depressions may be positioned at opposing corners of the generally parallelogram shaped configuration. The second and fourth depressions may be positioned at opposing corners of the generally parallelogram shaped configuration. The first and third depressions may be oriented generally perpendicular to each other. The second and fourth depressions may be oriented generally perpendicular to each other. The third depression may be orientated at a first angle. The second depression may be orientated at angle that is oblique to the first angle. The fourth depression may be orientated at angle that is oblique to the first angle.

Yet another aspect is a structure constructed from blow-molded plastic with a plurality of depressions formed into a predetermined pattern, such as rows and/or columns. For example, a first row of depressions may include depressions that alternate between a first orientation and a second orientation. The first and second orientations may be generally perpendicular to each other. A second row of depressions, which may be adjacent the first row of depressions, may alternate between a third orientation and a fourth orientation. The third and fourth orientations may be generally perpendicular to each other. The first orientation may be at an angle that is oblique to the third and fourth orientations. The second orientation may be at an angle that is oblique to the third and fourth orientations. The third orientation may be at an angle that is oblique to the first and second orientations. The fourth orientation may be at an angle that is oblique to the first and second orientations.

These and other aspects, features and advantages of the present invention will become more fully apparent from the following detailed description of preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended drawings contain figures of preferred embodiments to further clarify the above and other aspects, advantages and features of the present invention. It will be appreciated that these drawings depict only preferred embodiments of the invention and are not intended to limits its scope. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1A is a bottom perspective view of an exemplary embodiment of a structure constructed from blow-molded plastic, the exemplary structure being a blow-molded plastic table top;

FIG. 1B is a bottom view of a portion of the blow-molded structure shown in FIG. 1A, illustrating a plurality of depressions formed in a portion of the blow-molded structure;

FIG. 2A is an enlarged view of an exemplary embodiment of a depression;

FIG. 2B is an enlarged view of another exemplary embodiment of a depression;

FIG. 2C is an enlarged view of yet another exemplary embodiment of a depression;

FIG. 3A is a bottom view of the depression shown in FIG. 2C, illustrating an exemplary orientation of the depression;

FIG. 3B is a bottom view of the depression shown in FIG. 2C, illustrating another exemplary orientation of the depression;

FIG. 3C is a bottom view of the depression shown in FIG. 2C, illustrating yet another exemplary orientation of the depression;

FIG. 3D is a bottom view of the depression shown in FIG. 2C, illustrating still another exemplary orientation of the depression;

FIGS. 4, 5A, 5B, 6A, 6B, 7A, 7B, 8A, 8B, 8C, 8D, 9A, and 9B illustrate exemplary patterns of depressions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This invention is generally directed towards structures constructed from blow-molded plastic. The principles of the present invention, however, are not limited to blow-molded plastic structures. It will be understood that, in light of the present disclosure, the structures disclosed herein can be successfully used in connection with structures constructed from other types of materials and processes.

Additionally, to assist in the description of the blow-molded plastic structures, words such as top, bottom, front, rear, right and left are used to describe the accompanying figures. It will be appreciated, however, that the blow-molded plastic structures can be located in a variety of desired positions—including various angles, sideways and even upside down. A detailed description of the blow-molded plastic structures now follows.

As shown in FIG. 1A, a table top 2 may be constructed from blow-molded plastic. It will be appreciated, however, that a wide variety of structures may be constructed from blow-molded plastic including, for example, tables, chairs, walls, partitions, shelves, basketball backboards, storage bins, boxes, containers, sheds, sporting equipment, panels, fences and the like. One of ordinary skill in the art will also appreciate that all or a portion of these structures may be constructed from blow-molded plastic.

As shown in FIG. 1A, the table top 2 may include an upper or working surface 4 and a lower or mounting surface 6. The table top 2 may be supported by one or more legs or support pedestals, which are not shown in the accompanying figures. The table top preferably includes a hollow interior portion, which is preferably disposed between the upper surface 4 and the lower surface 6. The hollow interior portion is preferably integrally formed in table top 2 as part of a blow-molding process. It will be appreciated that the hollow interior portion may be filled with a material, such as foam or other suitable material.

The one or more legs or support pedestals are preferably movable between a first position in which the legs extend outwardly from the table top 2 and a second position in which the legs are positioned near and generally parallel to the lower surface 6 of the table top. In particular, the legs may each be pivotally or otherwise movably connected to the table top 2 and/or a table frame. Additionally, one or more support braces may be connected to the one or more legs and table top 2 and/or the table frame to help support the legs.

The table frame may include a first side rail and an opposing second side rail. Preferably, the first side rail is disposed substantially parallel to the second side rail, and the side rails preferably extend generally along the length of the table top 2. The length and configuration of the side rails may depend, for example, upon the length and configuration of the table top 2. In addition, the side rails may extend only a portion of the length of the table top 2. The side rails and/or the table top may include one or more apertures that are sized and configured to facilitate attachment of the legs and/or one or more cross bars to the frame and/or the table top. Advantageously, the frame may help prevent bowing, twisting, or deformation of table top 2, but it will be appreciated that table does not require the use of a frame and/or side rails.

The frame may be attached to a downwardly extending lip 8 located near the outer periphery of the table top 2. For example, the frame may be attached to an inner surface of the downwardly extending lip 8 by one or more fasteners. It will be understood that other suitable means or methods for attaching the frame to the table top 2 may be employed, including, but not limited to, rivets, screws, bolts, glues, epoxies, or other bonding materials.

It will be appreciated that the frame and the legs may be configured in a variety of ways, and the frame and legs may have other suitable designs, shapes and sizes. For example, the legs may include only a single elongated support member or multiple elongated support members, and the legs may be constructed as a single component or multiple components that are connected together. It will further be appreciated that the legs need not be in pivotal engagement with table top 2 to be collapsible. For example, the legs may be detachably connected to the table top 2 such that when it is desired to collapse the table for storage, the legs are detached from the table top.

Tables with other suitable features and configurations are disclosed in Assignee's U.S. Pat. No. 6,112,674, entitled PORTABLE FOLDING UTILITY TABLE WITH CENTER SUPPORT ASSEMBLY; U.S. Pat. No. 6,431,092, entitled PORTABLE FOLDING UTILITY TABLE WITH CENTER SUPPORT AND OFF-SET SUPPORT LEGS; U.S. Pat. No. 6,508,184, entitled LIGHTWEIGHT FOLDING TABLE WITH SELF-FIXTURING LEG ATTACHMENT; U.S. patent application Ser. No. 10/096,814 entitled PORTABLE FOLDING UTILITY TABLE WITH INTEGRAL TABLE TOP AND LIP, filed on Mar. 12, 2002; U.S. patent application Ser. No. 10/097,037, entitled PORTABLE FOLDING UTILITY TABLE WITH FRAME FASTENED TO INNER SURFACE OF LIP, filed on Mar. 12, 2002; and U.S. patent application Ser. No. 10/216,342, entitled TABLE WITH BLOW MOLDED TOP AND PIVOTALLY ATTACHED LEGS, filed on Aug. 10, 2002; and U.S. patent application Ser. No. 10/340,018, entitled PERSONAL TABLE, filed on Jan. 9, 2003. Each of these patents and applications are incorporated by reference.

The table top 2 may include a number of features that facilitate attachment of the legs, one or more cross bars, and/or the table frame to the table top. For example, the table top 2 may include mounting members and securing members that are preferably integrally formed in the table top as part of a unitary, one-piece structure. Preferred embodiments of suitable mounting members and securing members are disclosed in Assignee's U.S. Pat. No. 6,530,331, entitled PORTABLE FOLDING UTILITY TABLE WITH INTEGRAL RECEIVING MEMBERS, which is incorporated by reference.

As seen in FIGS. 1A and 1B, a portion 10 of the bottom surface 6 of the table top 2 may include a plurality of depressions 12 that are preferably sized and configured to increase the strength and structural integrity of the table top. The depressions 12 are preferably formed in the bottom surface 6 of the table top 2 and the depressions extend towards the upper surface 4 of the table top. As discussed in more detail below, the ends of the depressions 12 may contact or engage the upper surface 4 of the table top 2, or the ends of the depressions may be spaced from the upper surface of the table top.

The depressions 12 preferably cover substantially the entire bottom surface 6 of the table top, but it will be appreciated that the depressions may cover only a portion of bottom surface of the table top. Additionally, while the depressions 12 are shown and described as being located in the bottom surface 6 of the table top 2, the depressions could be formed in any desired portion of the table top and may cover only a portion of the table top.

The depressions 12 are preferably arranged into a predetermined pattern or array, which may increase the strength and/or structural integrity of the table top 2. In particular, the depressions 12 are preferably spaced closely together and the depressions may cover substantially the entire bottom surface 6 of the table top 2. Advantageously, the closely spaced depressions 12 may eliminates the elongated ribs and beams that were required in many conventional structures constructed from blow-molded plastic.

As shown in FIG. 1B, the depressions 12 are desirably formed into a predetermined pattern, such as rows. For example, the pattern may include one row of depressions 12 staggered with respect to an adjacent row of depressions. On the other hand, a row of depressions 12 may be aligned with an adjacent row of depressions 12. It will be appreciated that the depressions 12 may be formed in any suitable pattern or arrangement, including geometric, random, scattered, etc. depending, for example, upon the size and configuration of the table.

Desirably, the depressions 12 are formed in a predetermined pattern that minimizes or reduces the distance between the depressions. Advantageously, reducing the distance between the depressions may reduce the unsupported areas of the opposing surface. Reducing the distance between the depressions 12 may also increase the structural integrity and strength of the blow-molded structure. In addition, reducing the distance between the depressions 12 may increase the surface smoothness of the opposing surface. Thus, the depressions 12 are desirably closely spaced on the bottom surface 6 of the table top 2 such that the depressions are separated by a reduced distance. This may creates a table top 2 with greater strength and structural integrity, and the upper surface 4 of the table top may have increased smoothness.

Advantageously, the smaller distance between the depressions 12 may increase the structural integrity and strength of the blow-molded structure, which may allows the thickness of the outer wall of the blow-molded structure to be decreased. Accordingly, less plastic may be used to construct the blow-molded plastic structures because of the reduced outer wall thickness. Because less plastic is required to construct the blow-molded structure, that may allow the cost of the structure to be decreased. In addition, the blow-molded structure may cool more quickly during the manufacturing process because of the thinner outer walls. This may allow the blow-molded structure to be removed from the mold more quickly and it may allow the structure to be removed at a higher temperature because it dissipates heat more rapidly. Significantly, this may decrease the cycle time required to construct blow-molded structures and it may increase manufacturing efficiency.

Accordingly, increasing the number of depressions 12 and decreasing the distance between the depressions may increase the strength and structural integrity of blow-molded structures such as the table top 2. This is contrary to previous blow-molded structures that used strengthening ribs to increase the strength and structural integrity of the structures. Specifically, it was previously believed that stronger blow-molded structures were created by making the walls of the structure thicker and/or adding strengthening ribs. Disadvantageously, the thicker walls and strengthening ribs often required additional plastic and longer manufacturing times.

Increasing the number of depressions and decreasing the distance between the depressions provides the surprising and unexpected result that less plastic can be used to construct the blow-molded structures. Specifically, it was previously thought that a larger amount of plastic would be required because of the increased number of depressions in the blow-molded structure. The increased number of depressions, however, allows thinner outer walls to be used and that allows the overall amount of plastic used to construct the blow-molded structure to be decreased. Additionally, the increased number of closely spaced depressions 12 may increase the structural integrity of the structure, despite the fact that disruptions in the continuity of surface were previously thought to weaken the structure.

The depressions 12 are preferably arranged in a predetermined pattern to create a structure with generally uniform characteristics. For example, the depressions 12 are preferably arranged in staggered rows to decrease the distance between the depressions. Additionally, the depressions 12 preferably have a generally constant and uniform spacing across the surface of the structure. In particular, even if other features, objects or items are formed in the surface, the depressions 12 are preferably arranged into a generally uniform and consistent pattern. Thus, one or more depressions may be formed in the other features, objects or items formed in the surface. For example, one or more depressions 12 may be formed in channels or receiving portions located in the bottom surface 6 of the table top 2 in order to maintain a generally uniform and consistent pattern. In addition, the depressions 12 may be spaced about these other features, objects or items formed in the surface to keep a generally uniform and consistent pattern. Thus, the depressions are preferably spaced so that the distance between the depressions is minimized or otherwise reduced, substantially the entire surface is covered with depressions, and the depressions are located in a generally uniform and consistent pattern even if other features, objects or items are formed in the blow-molded structure.

In order to obtain a generally uniform and consistent pattern of depressions, it is generally desirable to eliminate or minimize or reduce other features, objects or items formed in the blow-molded structure. Thus, for example, strengthening ribs are preferably eliminated so that they do not interfere or disturb the generally uniform and consistent pattern of depressions.

As seen in FIG. 1B, the depressions 12 are preferably closely spaced to minimize or otherwise reduce the distance between the depressions. In particular, the depressions are formed in the bottom surface 6 and the depressions extend towards the upper surface 4 of the table top 2. Each of the depressions preferably includes a side wall and an end. The ends of the depressions 12 may contact or engage the upper surface 4 of the table top 2. Advantageously, this may help support the upper surface 4 of the table top 2 and the closely spaced depressions 12 may help to minimize the unsupported areas of the upper surface of the table top. The depressions 12 are preferably integrally formed in the table top 2 as part of a unitary, one-piece structure. In particular, the depressions 12 are preferably integrally formed in the table top 2 during the blow-molding process.

The depressions 12 are preferably sized and configured to allow the depressions to be closely spaced. In particular, the side walls of the depressions 12 are preferably formed at a steep angle to allow the depressions to be closely spaced. For example, the side walls of the depressions 12 are preferably at an angle between about 60° and about 85° relative to the lower surface 6 of the table top 2. More preferably, the side walls are positioned at an angle of 75° or greater with respect to the lower surface 6 of the table top 2. It will be appreciated that the side walls may be positioned at any desired angle relative to the lower surface 6 of the table top 2 depending, for example, upon the configuration of the depressions 12 formed in the table top 2.

The depressions 12 may have a height h generally equal to a thickness t of the table top 2, where the thickness t is the distance separating the lower surface 6 and the upper surface 4. When the depressions 12 have a height h generally equal to the thickness t of the table top 2, the ends of the depressions desirably contact or engage the upper surface 4 of the table top at a contact area. It will be appreciated that the size of the contact area may vary, for example, upon the shape and configuration of the depression. In addition, one or more of the depressions 12 may be separated by a distance d. The distance d is preferably measured from the center of one depression to the center of an adjacent depression. Desirably, the distance d separating adjacent depressions 12 is generally consistent so that a pattern of depressions with generally uniform and constant spacing is created.

It will be appreciated that the ends of the depressions 12 do not have to contact or engage the upper surface 4 of the table top 2. For example, the ends of the depressions 12 may be disposed proximate to and/or spaced part from the upper surface 4 of the table top 2. Thus, the height h of depressions would be less than the thickness t of the table top 2.

As discussed above, the distance d separating the depressions 12 is preferably minimized (or otherwise reduced) and the depressions are preferably located in a generally uniform and consistent arrangement so that the table top 2 is lightweight, high-strength structure with relatively uniform properties. In particular, the depressions 12 are preferably arranged in a tightly packed array that covers substantially all the lower surface 6 of the table top 2. For example, in order to create a tightly packed array of depressions 12, the distance d between adjacent depressions is preferably less than or equal to three times the thickness t of the table top 2. In order to create a more tightly packed array of depression, the distance d between adjacent depressions may be less than or equal to two times the thickness t of the table top 2. The distance d between adjacent depressions 12 may also be equal to or less than the thickness t of the table top 2. Additionally, the distance d between adjacent depressions 12 may be less than or equal to three times the height h of the table top 2. Further, the distance d between adjacent depressions may be two or less times than the height h of the table top 2. Finally, the distance d between adjacent depressions may be equal to or less than the height h of the table top 2. For example, in an exemplary embodiment, the distance d between adjacent depressions may be between about 1 to 3 inches, such as about 1.5 inches. It will be appreciated that the distance d may be larger or smaller depending, for example, upon the size, configuration and/or intended use of the table top 2.

As discussed above, conventional blow-molded structures often incorporated one or more reinforcing ribs or beams in an attempt to provide increased strength and support for blow-molded structures such as a table top 2. The closely spaced depressions 12, however, provide for the surprising and unexpected result that an increased number of depressions that are closely spaced together can create a stronger and lighter weight table top 2. Preferably, the depressions are consistently spaced over substantially all the entire surface of table top 2 so that substantially the entire surface of table top 2 is provided with increased strength and structural integrity. Advantageously, reinforcing ribs or beams may be eliminated so that the depressions can cover substantially the entire surface. It will be appreciated, however, that only a portion of the table top 2 may have a plurality of closely spaced depressions, for example, in order to provide increased structural strength to only those particular portions of table top 2. Further, the table top 2 may include reinforcing ribs or beams in any location, if desired.

The increased number of closely spaced depressions 12 may also allow blow-molded structures to be created with smoother, more planar surfaces. For example, the closely spaced depressions 12 may more uniformly support a surface and/or the surface may have more uniform characteristics. Thus, the surface may be smoother and generally located in the same plane. Advantageously, planar surfaces may be used to create a number of suitable objects, such as the table tops described above.

The depressions 12 may have a variety of shapes and configurations. For example, the depressions 12 may have a non-circular configuration such as the depressions 12 a shown in FIG. 2A. The generally oblong depressions 12 a may have a pair of opposing generally linear sides extending between a pair of opposing generally curvilinear ends. The depressions 12 may also have other suitable shapes and configurations such as the generally rectangular depression 12 b with rounded corners shown in FIG. 2B or the generally elliptical configuration shown in FIG. 2C. Of course, the depressions 12 could have other suitable shapes and configurations.

As shown in FIGS. 2A-2C, the depressions 12 a, 12 b, 12 c respectively may include a first axis 16 a, 16 b, 16 c and a second axis 18 a, 18 b, 18 c. The first axes 16 a, 16 b, 16 c are preferably centrally located and they may define a width of the depression, and the second axes 18 a, 18 b, 18 c may define a length of the depression. The widths 16 a, 16 b, 16 c of the depressions 12 a, 12 b, 12 c are preferably less than the lengths of the depressions 18 a, 18 b, 18 c, and the widths may advantageously be about 40 to about 60 percent of the lengths. The lengths of the depressions may also be about 1.5 to about 2.5 times the widths of the depressions, if desired. When the length of the depression is longer than the width of the depression, the axis 18 a, 18 b, 18 c may be referred to as the “major axis” and the axis 16 a, 16 b, or 16 c may be referred to as the “minor axis.” The relative lengths and widths of the depressions 12 may be larger, smaller, or the same depending, for example, on the particular configuration of the depressions.

Preferably, the axes 16 a, 16 b, and 16 c respectively intersect and/or are generally perpendicular to the axes 18 a, 18 b, and 18 c as shown in FIGS. 2A-2C. The axes 16 a, 16 b, 16 c and axes 18 a, 18 b, 18 c, however, does not have to be generally perpendicular. As shown in the accompanying figures, the depressions 12 a, 12 b, and 12 c respectively may also include a central portion 20 a, 20 b, and 20 c, which is preferably located at or proximate an intersection of the axes 16 and 18 and/or a center of the depression.

The depressions 12 may also have a generally symmetrical configuration. For example, as shown in FIGS. 2A-2C, the depressions 12 a, 12 b, and 12 c may be respectively symmetrical about the axes 16 a, 16 b, and 16 c and/or the axes 18 a, 18 b, and 18 c. Advantageously, the generally symmetrical depressions 12 a, 12 b, and 12 c may provide a more consistent, uniform strength, especially when applied in a variety of desired patterns of depressions. The depressions, however, do not have to be symmetrical.

It will be appreciated that the depressions 12 do not require a non-circular configuration, a generally oblong configuration or a generally symmetrical configuration. Further, the depressions 12 may have other suitable dimensions, shapes, and/or configurations, depending on the particular configuration of the table top 2. Depressions and/or blow-molded structures with other suitable features and configurations are disclosed in Assignee's U.S. patent application Ser. No. 10/409,000, filed Apr. 8, 2003 and entitled HIGH STRENGTH, LIGHTWEIGHT BLOW-MOLDED PLASTIC STRUCTURES, which is incorporated by reference.

As shown in FIGS. 3A-3D, the depressions 12 may be disposed in a variety of orientations relative to a reference axis 22, and these orientations may be used to arrange the depressions in a variety of patterns. Advantageously, the depressions may be arranged into patterns in order to increase the strength and/or decrease the weight of the table top 2.

For example, in an orientation 24, as shown in FIG. 3A, the axis 18 of the depression 12 may be generally aligned with the reference axis 22 and/or at an about 0 degrees angle relative to the reference axis. If desired, the axis 18 of the depression 12 may be spaced apart from the reference axis 22 and/or the depression 12; and the axis 18 may be generally parallel to the reference axis 22.

In another orientation 26, as shown in FIG. 3B, the axis 18 of the depression 12 may be at an oblique angle to the reference axis 22. This oblique angle may be between about 35 and 55 degrees, such as about 45 degrees.

In yet another orientation 28, as shown in FIG. 3C, the axis 18 of the depression 12 may be at an oblique angle to the reference axis 22. For example, the angle could be between about 125 and about 145 degrees, such as about a 135 degrees angle to the reference axis 22.

In still another orientation 30, as shown in FIG. 3D, the axis 18 of the depression 12 may be generally perpendicular to the reference axis 22, so that it is at about a 90 degrees angle to the reference axis 22.

As shown, the orientations 24 (FIG. 3A) and 30 (FIG. 3D) may be generally perpendicular to each other, and the orientations 26 (FIG. 3B) and 28 (FIG. 3C) may be generally perpendicular to each other. It will be appreciated that the depressions 12 may have other suitable orientations depending on the particular configuration of the table top 2.

As discussed above, the depressions 12 may have a variety of shapes, configurations, dimensions, and/or orientations. As shown in FIGS. 4-9B, the depressions 12 may be arranged in a variety of exemplary patterns, for example, to increase the strength and/or to decrease the weight of the table top 2. In addition, the depressions 12 may have different characteristics such as strength, rigidity, thickness and the like. Further, different portions of the depressions 12 may have different characteristics. For example, the depressions may be sized and configured to have increased strength along the length of the depression in comparison to the width of the depression. Thus, for instance, the depressions may have greater strength along a major axis and lesser strength along a minor axis. Advantageously, the depressions 12 may be arranged and/or configured to take advantage of these characteristics. In particular, the depressions 12 may be arranged to increase the strength and/or decrease the weight of blow-molded plastic structures.

As shown in FIG. 4, the depressions 12 may be arranged into a pattern 32 and the pattern may include rows 34, 36, 38 and 40. Each of the rows may include one or more depressions 12. For example, the row 34 preferably includes a plurality of depressions that alternate between the orientation 24 (as shown in FIG. 3A) and the orientation 30 (as shown in FIG. 3D); the row 36 preferably includes a plurality of depressions that alternate between the orientation 26 (as shown in FIG. 3B) and the orientation 28 (as shown in FIG. 3C); the row 38 preferably includes a plurality of depressions that alternate between the orientation 30 (as shown in FIG. 3D) and orientation 24 (as shown in FIG. 3A); and the row 40 preferably includes a plurality of depressions that alternate between the orientation 26 (as shown in FIG. 3B) and the orientation 28 (as shown in FIG. 3C). The pattern 32, as shown in the rows 34, 36, 38, 40, may be partially or completely repeated depending, for example, upon the size and configuration of the table top.

As shown in FIG. 4, the depressions 12 in the rows 34 and 38 are generally aligned, and the depressions in the rows 36 and 40 are also generally aligned. In particular, the depressions of the rows 34 are generally aligned with the depressions of the rows 38 in pairs along their center portions, and the depressions of the rows 36 are generally aligned with the depressions of the rows 40 in pairs along their center portions. Also, the depressions of rows 36 and 40 are generally offset to the depressions of rows 34 and 38 along their center portions. In particular, the rows 36 and 40 preferably include depressions spaced about half the distance between the depressions of the rows 34 and 38.

As shown, the generally aligned pairs of depressions 12 in rows 34, 38 preferably have orientatior is that are generally perpendicular to each other, and the generally aligned pairs of depressions in rows 36, 40 preferably have orientations that are generally perpendicular to each other. However, it will be appreciated that the depressions in the rows 34 and 38 need not be generally aligned or have particular relative orientations, and the depressions in the rows 36 and 40 need not be generally aligned or have particular relative orientations. In fact, the depressions could have any suitable arrangement and pattern.

As shown in FIG. 5A, the depressions 12 may be arranged in a pattern 42 with one or more rows and each row preferably includes one or more depressions. For example, the pattern 42 may include a first set of one or more rows (such as rows 44, 46) and second set of one or more rows (such as rows 48, 50). The one or more rows of the first set are preferably generally perpendicular to one or more rows of the second set. In particular, the row 44 preferably includes a plurality of depressions that alternate between the orientation 24 (as shown in FIG. 3A) and the orientation 30 (as shown in FIG. 3D); the row 46 preferably includes a plurality of depressions that alternate between the orientation 30 (as shown in FIG. 3D) and orientation 24 (as shown in FIG. 3A); the row 48 preferably includes a plurality of depressions that alternate between the orientation 24 (as shown in FIG. 3A) and the orientation 30 (as shown in FIG. 3D); and the row 50 preferably includes a plurality of depressions that alternate between the orientation 30 (as shown in FIG. 3D) and orientation 24 (as shown in FIG. 3A).

As shown in FIG. 5A, the row 48 is preferably generally perpendicular to the row 44 and/or the row 46, and the row 48 is preferably generally parallel to the row 50. Also, the row 50 is preferably generally perpendicular to the row 44 and/or the row 46, and the row 50 is preferably generally parallel to the row 48. Accordingly, the row 44 and/or the row 46 are preferably generally perpendicular to the row 48 and/or the row 50.

As shown in FIG. 5A, the row 48 includes at least one depression of the row 44 and/or at least one depression of the row 46, and the row 50 includes at least one depression of the row 44 and/or at least one depression of the row 46. Likewise, the row 44 includes at least one depression of the row 48 and/or at least one depression of the row 50, and the row 46 includes at least one depression of the row 48 and/or at least one depression of the row 50. It will be appreciated that the rows 44, 46, 48, 50 and the corresponding depressions 12 could have other suitable arrangements and configurations.

As shown in FIG. 5B, the pattern 42 may also include rows 52 and 54. The row 52 preferably includes a plurality of depressions that alternate between the orientation 26 (as shown in FIG. 3B) and the orientation 28 (as shown in FIG. 3C). The row 54 preferably includes a plurality of depressions that alternate between the orientation 28 (as shown in FIG. 3C) and the orientation 26 (as shown in FIG. 3B). As shown in FIG. 5B, the depressions of the rows 44 and 46 are generally aligned in pairs, and the depressions of the rows 48 and 50 are generally aligned in pairs along their center portions. Also, the rows 44 and 46 are generally offset to the row 52 along their center portions, and the rows 48 and 50 are generally offset to the row 52 along their center portions.

As shown in FIG. 5B, the row 52 is preferably generally parallel to the row 44 and/or the row 46, and the row 52 is preferably generally perpendicular to the row 48, the row 50, and/or the row 54. The row 54 is preferably generally parallel to the row 48 and/or the row 50, and the row 54 is preferably generally perpendicular to the row 44, the row 46, and/or the row 52.

As shown in FIG. 5B, the row 52 is preferably is preferably positioned between the row 44 and the row 46, and the depressions of the row 52 are generally offset to the depressions of rows 44 and 46 along their center portions. Also, the row 54 is preferably is preferably positioned between the row 48 and the row 50, and the depressions of the row 54 are generally offset to the depressions of rows 48 and 50 along their center portions. One of ordinary skill in the art will appreciate that the rows 44, 46, 48, 50, 52, 54 and the corresponding depressions 12 could also have other suitable arrangements and configurations.

As shown in FIG. 6A and 7A, the depressions 12 could be arranged into other suitable patterns. For example, the pattern 56 could include a plurality of rows including a first set of rows with rows 58, 60 and second set of rows with rows 62, 64. Also, as shown in FIG. 7A, the depressions 12 may be arranged a pattern 66 with a plurality of rows including a first set of rows with rows 68, 70 and second set of rows with rows 72, 74. As shown in FIG. 6A and 7A, one or more rows of the first set are preferably generally perpendicular to one or more rows of the second set, and one or more rows of the first set may intersect one or more rows of the second set to form a generally X-shaped configuration. Also, the rows of the first set are preferably parallel to each other, and the rows of the second set are preferably parallel to each other. Further, the depressions 12 of the one or more rows of the first set preferably have a first orientation, and the depressions of the one or more rows of the second set preferably have a second orientation that is generally perpendicular to the first orientation.

In greater detail, the depressions 12 may be arranged into a pattern of a plurality of rows with each row including a plurality of depressions. For example, the depressions 12 may be arranged a pattern 76 (as shown in FIG. 6B) including a first set of rows with rows 78, 80 and second set of rows with rows 82, 84. The depressions 12 may also be arranged a pattern 86 (as shown in FIG. 7B) including a first set of rows with rows 88, 90 and second set of rows with rows 92, 94.

As shown in FIG. 6B and 7B, each row of the first set of rows preferably includes a plurality of depressions that alternate between a first orientation and a second orientation, and each row of the second set of rows preferably includes a plurality of depressions that alternate between the second orientation and a third orientation. The first orientation and the third orientation are preferably generally perpendicular to each other. The second orientation is preferably at an oblique angle to the first orientation and/or the third orientation, at an about 45 degrees angle to the first orientation and/or the third orientation, and/or at an about 35 to about 55 degrees angle to the first orientation and/or the third orientation.

As shown in FIG. 6A and 7A, one or more rows of the first set are preferably generally perpendicular to one or more rows of the second set, and one or more rows of the first set may intersect one or more rows of the second set to form a generally X-shaped configuration. Also, the rows of the first set are preferably parallel to each other, and the rows of the second set are preferably parallel to each other. Further, one or more rows of the first set may each include at least one depression from some or all of the one or more rows of the second set, and one or more rows of the second set may each include at least one depression from some or all of the one or more rows of the first set. It will be understood that the rows and depressions 12 could also have other suitable arrangements and configurations.

As shown in FIG. 8A-8D, the depressions 12 may also be arranged a pattern of a plurality of depressions and the pattern could include a first depression, a second depression, a third depression, a fourth depression and a fifth depression. The first depression, the second depression, the third depression, and the fourth depression may be arranged in a generally square shaped configuration, a generally rectangular shaped configuration, and/or a generally parallelogram shaped configuration. The fifth depression may be disposed proximate the first, second, third, and fourth depressions. For example, as shown in FIG. 8A, the depressions 12 may be arranged a pattern 96 including a depression 98, a depression 100, a depression 102, a depression 104, and a depression 106. As discussed above, the depressions 98, 100, 102, and 104 could arranged in a generally square shaped configuration, a generally rectangular shaped configuration, and/or a generally parallelogram shaped configuration 108. As shown in FIG. 8B, the depressions 12 could be arranged into other suitable patterns. For example, the pattern 110 could include a depression 112, a depression 114, a depression 116, a depression 118 and a depression 120. The depressions 112, 114, 116 and 118 may be arranged in a generally square shaped configuration, a generally rectangular shaped configuration, and/or a generally parallelogram shaped configuration 122. In yet another example, as shown in FIG. 8C, the depressions 12 may be arranged a pattern 124 including a depression 126, a depression 128, a depression 130, a depression 132, and a depression 134; and the depressions 126, 128, 130, and 132 may be arranged in a generally square shaped configuration, a generally rectangular shaped configuration, and/or a generally parallelogram shaped configuration 136. In still another example, as shown in FIG. 8D, the depressions 12 may be arranged a pattern 138 including a depression 140, a depression 142, a depression 144, a depression 146, and a depression 148; and the depressions 140, 142, 144, and 146 arranged in a generally square shaped configuration, a generally rectangular shaped configuration, and/or a generally parallelogram shaped configuration

As shown in FIG. 8A-8D, the fifth depression may be disposed at or proximate the center portion of the generally square shaped, rectangular shaped, and/or parallelogram shaped configuration. The fifth depression may be substantially equally spaced from each of the first, second, third, and fourth depressions. The fifth depression preferably has an orientation at an oblique angle to, at an about 45 degrees angle to, at an about 35 to about 55 degrees angle to, and/or different from some or all of the respective orientations of the first, second, third, and fourth depressions. The patterns 96, 110, 124 and 138 may include the first, second, third, and fourth depressions without the fifth depression.

As shown in FIG. 8A 8D, the first and second depressions may have a first orientation and may form opposing corner portions of the generally square shaped, rectangular shaped, and/or parallelogram shaped configuration, and the third and fourth depressions may have a second orientation and may form opposing corner portions of the configuration. As shown in FIG. 8B, some or all of the first, second, third, and fourth depressions may each have a major axis intersecting the fifth depression and/or intersecting the center portion of the fifth depression. As shown in FIGS. 8A, 8C and 8D, some or all of the first, second, third, and fourth depressions may each have a major axis not intersecting the fifth depression. As shown in FIGS. 8A, some or all of the first, second, third, and fourth depressions may each have a minor axis intersecting the fifth depression and/or intersecting the center portion of the fifth depression. As shown in FIGS. 8B, 8C and 8D, some or all of the first, second, third, and fourth depressions may each have a minor axis not intersecting the fifth depression. One of ordinary skill in the art will appreciate that the depressions could also have other suitable arrangements and configurations.

As shown in FIG. 9A and 9B, the depressions 12 may be arranged into other suitable patterns, such as patterns 152 and 154. These patterns 152, 154 may include a first depression, a second depression, a third depression, and a fourth depression preferably arranged in a generally square shaped configuration, a generally rectangular shaped configuration, and/or a generally parallelogram shaped configuration, such as configurations 156 and 158. The first and second depressions preferably are proximate each other and form a first side of the generally square shaped, rectangular shaped, and/or parallelogram shaped configuration. The second and third depressions preferably are proximate each other and form a second side of the generally square shaped, rectangular shaped, and/or parallelogram shaped configuration. The third and fourth depressions preferably are proximate each other and form a third side of the generally square shaped, rectangular shaped, and/or parallelogram shaped configuration. The fourth and first depressions preferably are proximate each other and form a fourth side of the generally square shaped, rectangular shaped, and/or parallelogram shaped configuration. Accordingly, the first and third depressions may form opposing corner portions of the generally square shaped, rectangular shaped, and/or parallelogram shaped configuration, and the second and fourth depressions may form opposing corner portions of the configuration.

As shown in FIG. 9A and 9B, the first depression preferably has a first orientation, the second depression has a second orientation, the third depression has a third orientation, and the fourth depression has a fourth orientation. The first and third orientations are preferably generally perpendicular to each other, and the second and fourth orientations are preferably generally perpendicular to each other. In one embodiment, each of the first, second, third, and fourth depressions may have a different orientation. The first orientation and/or the third orientation may be at an oblique angle to the second orientation and/or the fourth orientation, at an about 45 degrees angle to the second orientation and/or the fourth orientation, and/or at an about 35 to about 55 degrees angle to the second orientation and/or the fourth orientation. Also, the second orientation and/or the fourth orientation may be at an oblique angle to the first orientation and/or the third orientation, at an about 45 degrees angle to the first orientation and/or the third orientation, and/or at an about 35 to about 55 degrees angle to the first orientation and/or the third orientation. One of ordinary skill in the art will appreciate that the depressions could also have other suitable arrangements and configurations.

The blow-molded plastic structure may include one pattern that covers all or just a portion of the structure. In addition, the structure may include different patterns, for example, on different portions of the structure. Thus, one or more of the patterns discussed above (such as patterns 32, 42, 56, 76, 66, 86, 96, 110, 124, 138, 152, and 154) may be used in connection with all or a portion of the blow-molded structure.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. 

1. A structure constructed from blow-molded plastic, the structure comprising: a first surface; a second surface that is spaced apart from the first surface; a hollow interior portion formed during the blow-molding process; a plurality of depressions formed in the second surface and extending towards the first surface, each of the plurality of depressions having generally the same general shape, the plurality of depressions comprising: a first depression, a second depression, a third depression and a fourth depression positioned in a generally parallelogram shaped configuration; and a fifth depression positioned proximate a central portion of the generally parallelogram shaped configuration, the fifth depression being orientated at first angle, the first depression being disposed at an angle that is oblique to the first angle, the second depression being disposed at an angle that is oblique to the first angle, the third depression being disposed at an angle that is oblique to the first angle, the fourth depression being disposed at an angle that is oblique to the first angle.
 2. The structure constructed from blow-molded plastic as in claim 1, wherein the first depression is oriented generally perpendicular to the second depression, the first depression is oriented generally perpendicular to the fourth depression, the second depression is oriented generally perpendicular to the first depression, the second depression is oriented generally perpendicular to the third depression, the third depression is oriented generally perpendicular to the second depression, the third depression is oriented generally perpendicular to the fourth depression, the fourth depression is oriented generally perpendicular to the first depression, and the fourth depression is oriented generally perpendicular to the third depression.
 3. The structure constructed from blow-molded plastic as in claim 1, wherein the first depression, the second depression, the third depression and the fourth depression positioned in a generally rectangular shaped configuration.
 4. The structure constructed from blow-molded plastic as in claim 1, wherein the first depression, the second depression, the third depression and the fourth depression positioned in a generally square shaped configuration.
 5. The structure constructed from blow-molded plastic as in claim 1, wherein the first, second, third, and fourth depressions each include a major axis that intersects a portion of the fifth depression.
 6. The structure constructed from blow-molded plastic as in claim 1, wherein the first, second, third, and fourth depressions each include a minor axis that intersects a portion of the fifth depression.
 7. The structure constructed from blow-molded plastic as in claim 1, wherein the depressions have a generally oblong configuration.
 8. A structure constructed from blow-molded plastic, the structure comprising: a first surface; a second surface that is spaced apart from the first surface; a hollow interior portion that is formed during the blow-molding process; a plurality of depressions formed in the second surface and extending towards the first surface, each of the plurality of depressions having generally the same shape, the plurality of depressions comprising: a first depression, a second depression, a third depression and a fourth depression positioned in a generally parallelogram shaped configuration, the first depression being disposed proximate the second and fourth depressions, the second depression being disposed proximate the first and third depressions, the third depression being disposed proximate the second and fourth depressions, the fourth depression being disposed proximate the first and third depressions; the first and third depressions being positioned at opposing corners of the generally parallelogram shaped configuration, the second and fourth depressions being positioned at opposing corners of the generally parallelogram shaped configuration; the first and third depressions being oriented generally perpendicular to each other; the second and fourth depressions being oriented generally perpendicular to each other; the third depression being orientated at a first angle, the second depression being orientated at angle that is oblique to the first angle, the fourth depression being orientated at angle that is oblique to the first angle.
 9. The structure constructed from blow-molded plastic as in claim 8, wherein the second depression is orientated at angle that is between about 35 degrees to about 55 degrees from the first angle, and the fourth depression is orientated at angle that is between about 35 degrees to about 55 degrees from the first angle.
 10. The structure constructed from blow-molded plastic as in claim 8, wherein the second depression is orientated at angle that is about 45 degrees from the first angle, and the fourth depression is orientated at angle that is about 45 degrees from the first angle.
 11. The structure constructed from blow-molded plastic as in claim 8, wherein the first depression, the second depression, the third depression and the fourth depression positioned in a generally rectangular shaped configuration.
 12. The structure constructed from blow-molded plastic as in claim 8, wherein the first depression, the second depression, the third depression and the fourth depression positioned in a generally square shaped configuration.
 13. The structure constructed from blow-molded plastic as in claim 8, wherein the depressions have a generally oblong configuration.
 14. A structure constructed from blow-molded plastic, the structure comprising: a first surface; a second surface that is spaced apart from the first surface; a hollow interior portion formed during the blow-molding process; a plurality of depressions formed in the second surface and extending towards the first surface, each of the plurality of depressions having generally the same shape, the plurality of depressions comprising: a first row of depressions, the depressions of the first row alternating between a first orientation and a second orientation, the first and second orientations being generally perpendicular to each other; and a second row of depressions adjacent the first row of depressions, the depressions of the second row alternating between a third orientation and a fourth orientation, the third and fourth orientations being generally perpendicular to each other, the first orientation being at an angle that is oblique to the third and fourth orientations, the second orientation being at an angle that is oblique to the third and fourth orientations, the third orientation being at an angle that is oblique to the first and second orientations, the fourth orientation being at an angle that is oblique to the first and second orientations.
 15. The structure constructed from blow-molded plastic as in claim 15, wherein the first orientation is between about 35 degrees to about 55 degrees from the third orientation, and the second orientation is between about 35 degrees to about 55 degrees from the third orientation.
 16. The structure constructed from blow-molded plastic as in claim 15, wherein the first orientation is about 45 degrees from the third orientation, and the second orientation is about 45 degrees from the third orientation.
 17. The structure constructed from blow-molded plastic as in claim 15, wherein the depressions of the second row are offset from the depressions of the first row.
 18. The structure constructed from blow-molded plastic as in claim 15, wherein the plurality of depressions further comprises: a third row of depressions adjacent the second row of depressions, the depressions of the third row alternating between the first orientation and the second orientation; and a fourth row of depressions adjacent the third row of depressions, the depressions of the fourth row alternating between the third orientation and the fourth orientation. 